ANTARCTIC PENINSULA ENVIRONS AS A SOURCE FOR NEW ANTIMICROBIALS

DANILOVICH, MARIANA; SANCHEZ, LEANDRO; ARNAU,GONZALO; FARIÑA, JULIA; DELGADO, OSVALDO

Cordoba

Congreso; XI CONGRESO ARGENTINO DE MICROBIOLOGIA GENERAL; 2015

SAMIGE

Antarctica is the biggest pristine area on Earth and represents one of the most valuable environments due to its microbialdiversity. It is indispensable to emphasize the study of pristine natural extreme-ecosystems since numerous biologically activecompounds including antibiotics, pesticides, hormones, growth factors, antioxidants, biosurfactants and enzymes have beenisolated from microorganisms belonging to them. In the medicinal area, research and development of novel compounds withantimicrobial activities has become in a priority due to the increased drug resistance in common bacterial pathogens along withthe emergence of new pathogenicity. To deal with this situation, a value-increasing strategy is on the spotlight: Bioprospecting.This process tends to direct search for metabolites with biotechnological importance from microbial isolates in naturalenvironments with specific characteristics. Based on this premise, thirteen cold-adapted isolates from soil and water samplessurrounding Antarctic Peninsula were studied for enzyme and antimicrobial production. The ability to produce biosurfactants wasalso tested. The enzymatic activities most frequently found among the isolates were as follow: lipase (46%), cellulase (23%),amylase (7%) and gelatinase (13%). Biosurfactant production was detected in 46% of the isolates. Three isolates were able toinhibit the growth of common food-borne pathogen bacteria and also some phytopatogens. The isolates 2D, 5D and 6D wereclosely related to Halomonas titanicae (99.8, 98.9, 96.7% respectively) by 16S rRNA gene sequencing. The profile of sugar wasstudied by the API 50 CHB system and other physiological characteristics by API 20NE systems and API 50CH. Growth rate atdifferent temperatures, pHs and NaCl tolerance were determined. The significant influence of culture media and incubationtemperature on antimicrobial production were evaluated, being LB-SW medium and 25°C the optimal conditions forantimicrobial production. Besides to marked tolerance to enzymatic treatment and negative net charge at pH 8.0 duringelectrophoresis, the antimicrobial compounds showed wide inhibition spectrum against both, G-positive and G-negativepathogenic and phyto-pathogenic bacteria. The antagonist compounds were produced during stationary phase of growth andconcentrated from cell-free supernatant by using SPE-C18 cartridges. The significance of this work lies in valuing pristineenvironments because of their importance as new sources of bioactive compounds and their possible role in agricultural orpharmaceutical biotechnological industries.